1. Field
The present application relates generally to the operation and design of analog front ends, and more particularly, to the operation and design of phase shifters for use in an analog front end.
2. Background
Beamforming transceivers having multiple antennas are typically utilized to transmit and receive signals over wireless links operating at millimeter wavelengths, for instance to transmit and receive signals at 60 GHz. Almost all beamforming applications are configured to have beamforming performed on RF signals, which requires the use of phase shifters that shift the phase of the RF signals that are transmitted or received over multiple antennas to form a desired beam pattern. Conventional phase shifters can be passive or active. Passive phase shifters can be shared between transmit (Tx) and receive (Rx) functions and have almost no power consumption, good linearity, and good noise performance. Unfortunately, the biggest challenges for conventional passive phase shifters are large signal loss and large group delay.
Accordingly, it would be desirable to have a simple and low cost passive phase shifter having low loss and small group delay.